A hearing-aid device with electret-microphone has been described in Bosch Publication No. 6 DRV, and in VKD No. 8 699 944 398-1131. Such a hearing-aid requires a voltage stabilizer circuit, which is connected in parallel to the battery powering the hearing-aid. The discrete components of the stabilizer circuit are located, on the common behind-the-ear-type of hearing-aid, on a printed circuit board. Space restrictions on the crowded circuit board place a lower limit on the possible size of such a hearing-aid and also limit the possibilities of upgrading the device performance by addition of further features.